Allium sativum L. (Garlic) bulb enlargement as influenced by differential combinations of photoperiod and temperature

Abstract

Photoperiod and temperature are vital environmental factors that regulate plant developmental processes. However, the roles of these factors in garlic bulb enlargement are unclear. In this report, responses of garlic bulb morphology and physiology to combinations of photoperiod (light/dark: 10/14 h, 12/12 h, 14/10 h) and temperature (light/dark: 25/18 °C, 30/20 °C) were investigated. For garlic cultivar G103, bulb characteristics, phytohormones (IAA, ABA, ZT, tZR, JA), allicin and phenolic acids (p-coumaric and p-hydroxybenzoic) were highest under a photoperiod of 14 h at 30 °C. Maximum GA was observed under 14 h + 30 °C for cv. G2011-5. Maximum caffeic, ferulic and vanillic acids were detected for cv. G2011-5 at 14 h + 30 °C, 12 h + 25 °C and 14 h + 25 °C, respectively. Flavonoids (myricetin, quercetin, kaempferol and apigenin) were not detected in this trial. This is the first report describing the impact of long periods of light duration and higher temperatures on garlic morphology, phytohormones, phenolic acids and allicin content.

Keywords: Abscisic acid (PubChem CID: 5280896); Allicin; Allicin (PubChem CID: 65036); Bulbing index; Caffeic acid: (PubChem CID: 689043); Ferulic acid: (PubChem CID: 445858); Garlic; Gibberellic acid (PubChem CID: 6466); Indole-3-acetic acid (PubChem CID: 802); Jasmonic acid (PubChem CID: 5281166); Phenolic compounds; Photoperiod; Phytohormones; Temperature; Vanillic acid (PubChem CID: 8468); p-Coumaric acid: (PubChem CID: 637542); trans-Zeatin riboside (PubChem CID: 6440982).